Because You Promised
by myshipperheart17
Summary: Captain Swan, set immediately after 5x08 (and with direct reference to the 5x10 promo) - the episode that broke all of our hearts! SPOILERS for season 5, up to 5x10. I do not own these wonderful characters, the amazing OUAT team do. I just love them.
1. Chapter 1

**After the joy and simultaneous horror that was 5x08, I'm writing this to get me through to 5x10!**

* * *

It had been three hours since he had disappeared from her living room in a swirl of inky black smoke, leaving her broken and alone. Vulnerable wasn't a feeling she had imagined a Dark One could experience, but she had been wrong. About that and about so many other things.

Zelena had fled when she realised quite how messy things were about to get. Her crazed laugh as she vanished was the last sound to echo around the dimly lit room for minutes after she was gone, an uneasy silence enveloping them as they stood staring at each other. Neither one willing to be the first to look away. Lately, in any moment like this, when their eyes locked, it wouldn't have taken long for one of them to lean in, close that gap and kiss the other. This time there was a different kind of electricity flying between them, and it scared her. Not because for a minute she thought he would ever hurt her, but because for the first time since she made that decision and tethered him to Excalibur, she allowed herself to admit that she ignored what _**he**_ wanted. She ignored his plea not to turn him into the one thing he hated more than anything, ignored his words when he told her he wasn't strong enough to cope with that much darkness, because _**she**_ believed he could. She wanted nothing more than to spend the rest of her life with him, and she never stopped to consider his wishes. And while she'd do it all over again, save him from death a million times over for even the tiniest possibility that they could be together, she could now admit to herself, seeing the anger in his eyes, that he might not forgive her this time.

Every time he told her he loved her, that she could never do anything to make him think less of her, that he already forgave her, she had grasped hold of it, desperately hoping that that was true. But he could never have imagined this was where they'd end up.

"Killian…" she finally whispered, her eyes glassy with tears, as she took a tiny step towards him.

"Don't call me that," he bit back, a venom in his tone she had never heard him use with her before. A tone she hadn't heard him use with anyone, "Not when I'm this. When I'm what you've made me."

Before she could speak again, it started. A tirade of hateful words, his tone swinging from red hot fury to devastation and back again within seconds. He was pacing, storming around the living room of the home he had chosen for them, knocking anything in his path out of his way. But rarely did he look at her, or direct any of the angry words at her. It was like he had snapped, and wasn't even aware she was still there. So instead of trying to explain, or to intervene, she simply sat down on the stairs, cried, and let him get it all out of his system.

Minutes later, he'd stopped in his tracks, turned to look at her and disappeared.

Every ounce of her being had wanted to follow him there and then, chase him down, make him listen. But a sensible voice somewhere in the recesses of her brain, one that sounded a lot like her mother, had talked her out of it. A little space couldn't hurt either of them, she'd decided.

But now it was three hours later and she'd had enough. In the space of just a few hours, she had gone from reuniting with him, hearing him tell her he loved her no matter what, kissing him and thinking that just maybe they stood a chance, and now? Now this. Now, because of Zelena, her plan to fix all of this as painlessly as possible had been ruined. And what she needed more than anything else at a time like this, was to see him, wrap her arms around his waist and breathe in the scent of that familiar leather jacket. The one person she needed was the one person who wanted nothing to do with her.

Without thinking, she transported herself out of the house and found herself on the pier, walking slowly towards the Jolly Roger. She hadn't even really thought about it - it just made sense to her that he'd come here. Where else would he go?

Before she even made it to the ship though, she spotted him. He was sitting on the edge of the pier, leaning forward to look into the choppy, dark water. His shoulders tensed as she approached, but he didn't move, when he could easily have transported himself away from her.

She took a deep breath, and risked sitting down beside him, keeping enough distance that their bodies weren't touching. She joined him in staring into the water, the irregular movement of the waves having a strangely soothing effect on her. He was right when he said the sea was calming.

She wasn't sure how long they sat there for before he broke the silence.

"I can't tell you everything's going to be okay this time," he whispered. His voice was rough, deep and sounded about as broken as she felt.

She found herself nodding, instinctively reaching up to swipe away the tear that had found its way onto her cheek.

"I know that."

Silence fell again, and she wondered if she should leave. As if he had read her mind, he inched the slightest bit to the right, towards her, his leg still not brushing against hers, but a sign that he wasn't about to run out on her again.

She pulled the chain around her neck out from under her leather jacket, twirling the ring her gave her, Liam's ring, around her fingertip.

He glanced at her, watching her stare at the ring, and a conflicted look passed over his face. He looked pale and drained, but still perfect to her.

"I wish you hadn't stopped me remembering, Emma. I wish you hadn't taken away all those moments we shared."

His voice was shaking, and it took everything in her power not to throw herself at him, lock her arms around him and never let go.

"I couldn't let you see what I'd done to you… and if I'd let you remember the good parts, but not the end, you'd have been even more hurt and confused. I couldn't bear you knowing how perfect everything had been just to see how I ruined it."

There was no sense in swiping the tears away now. They were in full flow.

"You gave me this ring as a reminder of the fact you loved me. You chose a house for us. I finally told you how I really felt, how much I love you, and then I was about to lose you. And I chose to save you because I couldn't handle coming back to Storybrooke without you. I've lost so many people, Killian, but I just couldn't lose you. And now I've saved you, but in what might be the worst way possible, and I'm going to end up losing you anyway."

She was crying too hard now to make sense, and she struggled to catch her breath. She clutched the ring on the chain close to her chest, closing her eyes to block it all out.

"It's just not fair. None of this is fair."

Her eyes flew open when she felt his leg against hers, and seconds later his arm wrapped around her shoulder. She dissolved even more, burying her face in his neck and sliding her arms around his waist.

When her breathing eventually settled, she remained snuggled into his side, her palm splayed open on his chest where she so often found it resting.

"I'm sorry for my behaviour in the house," he said, quietly.

She pulled back and tilted his face towards her, her heart breaking to see that his face was about as tear stained as her own.

"I know. That wasn't you. That was the darkness… kicking in, I guess."

He shook his head, turning away from her, that little muscle tensing in his jaw the way it always does when he worries.

"That's the problem. That's why I didn't want to go through this. Darkness or not, I can't control it. I'm not like you."

He sounded like he was giving up and she refused to let him go down this road without a fight. Tilting his face back to hers, her hand tangled in his hair.

"You're exactly like me," she whispered, "We've both got light and dark inside of us, and we can fight this. We have to fight this together."

His eyes shone with tears again, as he desperately blinked them back, still refusing to meet her eye.

"Why?" he finally asked.

"Because you promised me a happy future, and I need you to keep that promise. And because I love you more than I thought it was possible to love someone."

She could have sworn she saw a glimmer of hope cross his face when she said it, that "I can't quite believe what I'm hearing" expression he wore in Camelot when she told him she loved him too, and that she wanted a future with him.

"Killian, please don't hate me for doing what I had to do to keep you alive. I believe in us. We're in this together. If we can get through this, which I know we can, then we can get through anything. And this horrible, terrible experience, is something only the two of us will ever understand. Don't let me do this alone."

Before he could respond, she did what she had been fighting the urge to do this whole time. She pulled him to her and kissed him.

He was slow to react, but when he eventually did, she wondered if perhaps she shouldn't have let this happen. They might be vulnerable, but they were both Dark Ones. Fiery and impulsive… the kiss spiralled from a tender moment of hope to a blur of passion, fuelled by fear and anger and love and lust. It took physically transporting herself to a few feet away from him for her to be able to stop. Not only wasn't it the time, but the pier was hardly the place.

He stared at her breathlessly, his expression now unreadable, and he shook his head, turning back to face the water. He ran his hand through his hair and as more and more seconds passed, he walked further away from her along the pier. Unable to face him walking away, after everything she'd just said, she decided now was the time to leave.

"I'll be at the house… if you want to talk."

She disappeared before he could answer. She didn't think she could handle the rejection if he said no.

* * *

Dark Ones don't need sleep, but she lay in bed anyway, tossing and turning as the hours ticked by. It was like living in a nightmare she didn't know how to get out of. Everything she had spent so long running from had finally been in her grasp, and then it was ripped away.

She tired of staring out of the window and rolled back over towards the door of what would have been their bedroom. She tensed as she felt that prickle that ran over her skin whenever someone was near, a sense she had been given alongside all the other delights of being the Dark One.

Seconds later he appeared at the door out of nowhere, leaning against the doorframe. He didn't say a word, just stared at her for a second, before walking towards her and sitting down on the bed beside her.

"Couldn't sleep…" he said, trying his usual sarcastic tone, but the smile didn't meet his eyes.

She reached out and took his hand, squeezing his cool fingers against her equally cold palm. He swung his legs up on to the bed and she instinctively curled into his side, one hand on his chest while the other still clutched his.

They lay in silence for what felt like hours, but could have been minutes. It didn't matter. He was here.

"I still can't tell you everything's going to be okay," he finally whispered against her hair.

"I know," she replied.

But it was a start.

* * *

 **I just needed to write something that felt marginally hopeful! Reviews very welcome!**


	2. Chapter 2

**This was originally a one-shot, but I couldn't resist keeping going with it! Especially since we're episode-less this week. Based on the 5x10 promo...**

Morning came, the soft dawn light flooding the room with a gentle glow. It had been hours since either one of them had spoken, or even moved. His thumb rubbed absent minded circles against her arm every now and then, and she'd glance up to see his eyes firmly closed, his way of blocking it all out.

She was still trying to figure out where she was supposed to go from here. Realistically, her plan was still solid - find a way to capture Zelena again, and use her as a vessel to destroy the darkness. It was the strangest sensation. Half of her, the real Emma, felt utterly sick at the thought of it. But Dark Emma, this thing that had rooted itself in her, relished the thought. It justified her plan with whispers of "She hurt Regina" and "She killed Neal" and "The world would be a better place without her" - and that rationalisation was something that Killian hadn't seemed to agree with. Surely now though, now that he knew the truth, he would see that it was the only chance they had?

She had work to do. The darkness wasn't going to destroy itself. But something told her that this silent bubble, where she had him here holding her, wasn't going to last much longer, and she refused to be the one to let go first. The whole reason she had done this was to keep him with her. The darkness had existed for thousands of years - it could wait another hour or so to be destroyed.

"Can I ask you something?"

His voice took her completely by surprise, the gruff sound, having not spoken for hours, reverberating around the room.

"Anything," she replied, her tone as confident as she could muster.

His hand had moved up from her arm to her hair, which she had let down from that severe bun, and he ran his fingers through the long blonde strands.

"Would you ever have told me?"

She didn't have to ask what he meant. And honestly, she didn't have an answer, because she'd never allowed herself to think that far ahead. This whole time, everything she was focused on was leading up to destroying the darkness, and thinking about anything after that had been too risky.

Telling him was what she had been afraid of, because she knew that he would hate her for turning him into this. So if she could have avoided it, let him live in blissful ignorance, never let him know what he had done in that short time they were the Dark Ones together in Camelot, she would have.

But not telling him would have meant keeping all of the Camelot memories from him, and from everyone else. It would mean he'd never feel that giddy exhilaration she felt every time she thought about their horse ride through the the meadows, the rush of love that had flown over them when he'd given her Liam's ring and told her to come home to him, or the joy that she'd seen on his face when she told him how much she wanted him and their future together. Wasn't all of that worth more than the risk of him being angry with her?

"Honestly… I hadn't thought that far ahead…" she whispered.

"But?"

"But yes. I would have told you. I mean, I might not have had a choice in the matter - I have no idea what's going to happen to us when I end this nightmare. But if I could have made the choice, I would have told you. Once you were safe. I wouldn't have wanted to keep your memories from you forever. What we shared in Camelot meant too much to both of us for me to hide it from you."

Her words hung in the air as he lay in silence, his hand stilling in her hair. Minutes passed without a response, and she felt sick. Before this, any declaration of love or affection from her would have had him in pieces, pulling her close, kissing her, showing her how much he adored her. She had to know that this would happen, but it didn't make it any easier to swallow now that it was a reality.

"What was your favourite part?" he asked. His voice was cool and even, not quite emotionless, but certainly not the warm tone she was used to. It wasn't too far removed from her own voice these days, that low, no-nonsense way of speaking she had developed since the darkness had fully taken hold.

"Every part of it was special. But the day you took me horse riding, when we talked to Henry about Violet in the stable… I watched you with him. The way you teased him, the pride in your face, and the way he made us hide when she was about to walk in. That day, despite everything we were going through, we felt like a real family. And even though the darkness was still there, in my head, that gave me hope. Then when I found out that you two had been looking at houses for us, I knew. I already knew I loved you so much it scared me, but seeing how you've bonded with my kid… that was it. That was when I realised I couldn't begin to imagine my life without you any more. That was when I knew that a future with you was more than I could ever have hoped for, and I would do everything I could to get us back to it. That's what had me feeling overwhelmed when Regina came and talked to me. And then I told you, and you kissed me, and that's what lit the flame. Before everything got messed up."

He had let her talk and not once tried to interrupt. She had said all of that to his chest, never looking up to meet his gaze.

He tangled his fingers in her hair again and tugged gently at it, forcing her to look up at him.

"You know that's all I ever wanted to hear, don't you?"

"I know."

"And I knew it. I knew you loved me. And you would have been safe."

"I told you. That wasn't enough for me."

She pushed herself up on her elbow, her face level with his.

"Not when what we have is this good."

His eyes were dark, stormy, staring at her in that way he had when she'd once accused him of trying to "drill a hole in her head".

She felt her pulse quicken as she reached up to trace the line of his jaw and down his neck to his collarbone. She knew this was a mistake, but she couldn't resist. That familiar stirring in her, a combination of her attraction to him and the powerful feeling her dark magic gave her, that feeling she tried to hard to ignore, mixed together, igniting something dangerous inside her.

She leaned in and pressed a kiss to his neck, feeling his entire body tense.

"Don't tell me you'd rather have died than be here with me…"

He cut her off with his mouth, kissing her hard, that passion that had sparked between them down on the pier the previous night taking hold.

And moments later, just as suddenly, once again they separated. Only this time, it wasn't her who initiated it. He dragged his lips from her and in the blink of an eye he was standing by the door.

"Well…" she finally mumbled, "You certainly have more self control right now than I do. Maybe the darkness isn't controlling you the way you said it would."

A flash of anger passed over his face, and she visibly saw him take a breath before he spoke.

"I just can't do this now. Not when I'm this angry."

She slid over to the end of the bed and stood, walking slowly towards him.

"What can I do? What do you need me to do?"

He didn't pull back when she threaded her fingers through his.

"I don't know."

She took the chance that he wouldn't push her away, and she leaned into him again, gently pressing a kiss to his lips.

"When we were in Camelot and Rumplestiltskin was stuck in my head, you made him go away. You made everything feel better. I did this… so I want to help you the way you helped me. I need to."

She knew something she'd said he hit a nerve, from the look that he gave her. His expression, which had softened before, had turned to ice again.

He let go of her hand and turned to walk down the stairs.

"Where are you going?"

He didn't hesitate, didn't so much as glance back at her as he continued down into the living room.

"I have some people I have to see," he said, that venom back in his voice that had scared her the night before.

She went over her previous sentence, searching for a clue.

Rumplestiltskin.

He was going after Rumplestiltskin. And right now, in the state he was in, that could only end in tears. It had taken all his strength not to lash out at her, and he loved her more than anything. That didn't bode well for the person he'd dedicated most of his life to hunting down.

She saved him to protect their future, and killing Rumple was certainly not part of that plan. Just like it was up to him to protect her heart, it was up to her to protect his. She wouldn't let the darkness make him into a monster.

She had to stop him.

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 **Hope you enjoyed this, even if it isn't particularly imaginative (running with the direction the promo is taking us in!). Reviews make me smile! :)**


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